Submersible fuel pump

ABSTRACT

A rotary electric fuel pump using a permanent magnet motor is constructed of parts having a simple geometric pattern for mass production by sheet metal stamping and plastic molding. The construction provides for housing a cylindrical magnet stator for a motor field and a high-speed armature. The fuel medium being pumped flows over the magnet effecting cooling, with some diverting of flow through the armature for cooling. A further feature resides in the construction of an impeller having flow passage to the stator slots phased in such a manner that peak flow pressure at the slots is evened out around the impeller. Thus, the impeller vane spacing is related to that of the stator slots that only one flow pressure peak occurs at a time, and such peaks occur sequentually at widely spaced points around the rotary axis. This minimizes electric current peaks and brush sparking as well as bearing wear. The construction is fully sealed for submerged use in fuel tanks.

nited States Patent [191 lJlm et al.

[ Nov. 27, 1973 SUBMERSIBLE FUEL PUMP [75] inventors: Ralph E. Ulm;Claude F. Phillips;

" Michael J. Sullivan; Larry C.

Collins; William Russell Parrent, all of Fairfield, Ill.

[73] Assignee: V Airtex Products, Division of United IndustrialSyndicate, New York, NY.

22 Filed: Feb. 10, 1972 211 App]. No.: 225,330

Related US. Application Data [62] Division of Ser. No. 37,951, May 20,1970, Pat. No.

Primary Examiner-C. J Husar Attorney-Albert M. Zalkind [57] ABSTRACT Arotary electric fuel pump using a permanent magnet motor is constructedof parts having a simple geometric pattern for mass production by sheetmetal stamping and plastic molding. The construction provides forhousing a cylindrical magnet stator for a motor field and a high-speedarmature. The fuel medium being pumped flows over the magnet effectingcooling, with some diverting of flow through the armature for cooling. Afurther feature resides in the construction of an impeller having flowpassage to the stator slots phased in such a manner that peak flowpressure at the slots is evened out around the impeller. Thus, theimpeller vane spacing is related to that of the stator slots that onlyone flow pressure peak occurs at a time, and such peaks occursequentually at widely spaced points around the rotary axis. Thisminimizes electric current peaks and brush sparking as well as bearingwear. The construction is fully sealed for submerged use in fuel tanks.

3 Claims, 11 Drawing Figures SUBMERSIBLE FUEL PUMP This is a division,of application Ser. No. 37,951 filed May 20, 1970, now US Pat. No.3,666,381.

Briefly, the invention in a preferred form comprises a steel housing orshell of generally cylindrical shape but formed with radial depressions.A cylindrical ceramic magnet of known type is used as a DC. motor fieldcarried within the shell and an armature rotates within the magnet.Current to'the armature is brought in via a commutator and radiallydisposed brushes. The construction permits of inlet and outlet bodymembers formed of molded plastic locked within the steel housing andproviding bearing support for the armature, as well as support for thebrushes. The cylindrical magnet is radially supported by the sleevedepressions, radially spaced within the sleeve, and longitudinallylocked by the body members in conjunction with an intermediate pumpstator. A complete flux trap, or substantially so, is provided for themagnet by the sleeve whereby all flux is confined within the sleeve andonly minimum stray magnetic leakage may occur.

A centrifugal pump impeller of molded plastic is keyed to the armatureshaft, being of conical shape having equally spaced radial vanes, theperiphery of which is surrounded by a collar formed of the pump stator.The stator collar is slotted to take flow radially outward of the vanesand direct it longitudinally through the radial spacing between theouter sleeve and magnet.

The flow passes longitudinally over the outer surface of the cylindricalmagnet to an annular outlet channel which connects to an outlet conduitintegrally molded with the outlet body member.

The stator slots are numerically unequal to the impeller vanes and atsuch ratio numerically thereto that although equiangularly spaced, theoutput flow from the vanes through the slots occurs in a predeterminedtime order of flow peaks so that flow through each slot has a dischargepeak to the output channel at a specific time in each rotation of theimpeller. Accordingly, flow pulsation at maximum pressure occurringsimultaneously from a plurality of slots is avoided and thus the pumpoperates with a minimum of shock and vibration.

The time pressure pulsations are spaced to apply the torque load throughequally spaced increments, reducing the magnitude of the peak to peakelectric current pulses of the electric motor driving the impeller andreducing sparking of the brushes. Also, due to the angular spacing ofthe impeller passage means in respect to the stator passage means, therelative orientation around the impeller shaft of radial reaction forcesat peak pressures is widely distributed which minimizes bearing wear.

A detailed description of the invention now follows in conjunction withthe appended drawing in which:

FIG. 1 is a section through a preferred form of the invention takenlongitudinally;

FIG. 2 is a radial section through 2-2 of FIG. 1 showing the impellerand stator relationship;

FIG. 3 is a section through 3-3 of FIG. 1, omitting the armature;

FIG. 4 is a radial fragmentary section of modified construction of theimpeller;

FIG. 5 is an exploded section of an impeller and stator in partialassembly;

FIG. 6 is a detail shown fragmentarily of the commutator brushconstruction in partial cross section, taken at right angles to FIG. 1;

FIG. 7 is an exterior view of one end of the pump;

FIG. 8 is a longitudinal exterior view;

FIG. 9 is an exterior view of the other end of the FIG. 10 is alongitudinal section of a modified pump and construction;

FIG. 11 is a fragmentary radial section through 1l11 of FIG. 10.

Referring to FIGS. 1 thru 9, the preferred form of the inventioncomprises a generally cylindrical steel sleeve or shell 10 closed atboth ends by body member means such as the plastic body member 15 at theinlet end and plastic body member at the outlet end. The inlet end ofthe shell is radially deformed to fit tightly and sealingly against aconical shoulder 23 of a molded plastic body member 15 which abuts apump stator 27, the stator in turn abutting a ceramic magnet ofcylindrical shape. The oher end of the magnet is abutted by moldedplastic body member 20 in turn sealingly locked within sleeve 10 by theinwardly directive radial flange 34. Accordingly, magnet 30 islongitudinally locked in the shell 10 by the body members and preventedfrom rotating by a tongue of body member 20 protruding into a notch 36of the magnet.

Shell 10 is provided with arcuate depressions 38, a pair of suchdepressions being diametrically opposed as seen in FIG. 3, and themagnet 30 is radially disposed and located concetrically within shell 10by being contiguous within the inner surfaces or walls of thedepressions 38. Accordingly, the construction thus far described looksmagnet 30 radially and longitudinally and affords large arcuate flowrecesses intermediate the depressions 38 which recesses or passagesextend longitudinally over magnet 30.

Inlet body member 15 has an entrance collar 47 around which is seated afilter tube 50 (fragmentarily shown) which tube which is understood tobe made of any suitable filter material. When the pump is submerged in afuel tank, fuel can pass thru the filter tube into collar 47 and inletports 55 to the hub of an impeller 60, there being three inlet portssuch ports 55 as noted on FIG. 9.

A molded plastic impeller of conical form is provided having a pluralityof vanes 64 equiangularly disposed and conically slanted as shown, beingdisposed in radial planes. As seen in FIG. 2, the specific embodimentbeing described has seven such vanes peripherally surrounded by a collar68 of stator 27 which collar is essentially cylindrical but providedwith twelve equiangular disposed slots 72 separated by fingers 74. Theslots provide longitudinally flow passages for centrifugal flow inducedby the impeller and directs such flow to the recesses 44. It will beunderstood that collar 68 is thus longitudinally open at the beginningand end of each slot 72 and that the fingers 74 of the collar abut attheir upstream ends with body member 15.

The stator 27 has a dowstream collar 76 extending into engagement withmagnet 30. Accordingly, as heretofore mentioned, the stator is anabutment member between body member 15 and magnet 30 at the upstream endof the magnet. At the downstream end of the magnet, body member 20 isformed with a continuous wall 76 effecting a radial edge 79 abutting themagnet. Body member 20 is also suitably formed with a radial flange 80which seats against shell flange 34 and the molding which forms bodymember 20 is provided with an internal annular outlet channel 82circumferentially surrounding wall 78 and from which channel extends anoutlet conduit 84 all integrally molded therewith. Any suitable tubingcan be connected to conduit 84 for fuel discharge from the pump leadingout of the fuel tank to an engine carburetor, in a well understoodmanner.

Referring to the foregoing it will be understood that ingress of fuelvia filter 50 can be centrifugally pumped by rotation of impeller 60whence fuel discharge is directed through slots 72 of stator 27longitudinally to recesses 44, over most of the exterior areas of magnet30 and thence to outlet channel 82 and conduit 84.

It will be appreciated that the radial spacing between the magnet andshell although not completely about the periphery of the magnet issufficient to permit flow without undue restriction.

Rotation of the impeller is effected by an armature 88 of a DC permanentmagnet motor, the magnet 30 being the flux field therefore. The armaturehas a commutator 92 and a shaft 96 extending thru the construction, in aconventional manner, and to which the impeller is keyed, wherein one endof the shaft has suitable bearing in body member and the other end hassimilar bearing in body member 20. The bearing surfaces are, of course,coaxial with the shaft and are provided by the hubs 100 and 103 moldedinto the respective body members as shown. In the case of the downstreamend of the shaft 96, the hub 100 is elongated for purposes ofaccomodating a ball and spring whereby the ball is pressed against therespective shaft end to bias the armature into a predetermined positionwherein the other end of the shaft has its end abuting the closed end ofhub 103.

As seen in FIG. 6 a radial brush arrangement is preferred and suitablebosses 108 are integrally molded with the body member to accomodatecommutator brushes 112 spring biased and retained by capa 115 whichsecure connection terminals 118 all in a conventional manner wherein thecaps may be welded to the body member 20, as shown.

In order to provide for internal cooling of the motor a small passageway120 is slotted through collar 76 whence flow from the stator can to anydesired extent be diverted into the armature region to flow through thearmature within the housing therefore provided by the body members andthe magnet, such flow having egress via a slot 125 at edge 79 in bodymember 20 into outlet conduit 84. Thus any desired amount of coolingflow would be provided which flow is continuous for cooling thearmature, whereas general cooling of the motor is afforded by thelongitudinal flow over the magnet. The magnet is thus kept cool whileabsorbing heat from fuel passing through the armature chamber therebyaugmenting the cooling effect on the armature.

An important feature of the invention resides in the fact that thenumerical ratio of impeller vanes to stator slots is such as to permitphasing of vane progression passing the slots in a timed order so thatflow peaks occur in a predetermined sequence and never simultaneouslyfrom any two slots. Thus, as seen in FIG. 2 the progression of flowpeaks will be in accordance with numerals 1-7 noted on the vanes, thedirection of rotation of the impeller being counterclockwise asindicated by the arrow. By providing 7 vanes and 12 slots there are 12flow peaks per rotation of the impeller for each vane occurring in thenumerical order l-2-3-4-5-6-7, shown on FIG. 2. It will be noted thatflow peaks occurring through the slots are separated as to respectiveslots by a wide angle, about as seen on FIG. 2. This geometricallydistributes the flow peaks about the periphery of the stator to minimizereactive forces. In other words, peak flow caused by vane l is followedby peak flow caused by vane 2 and then peak flow caused by vane 3, etc.,all such peak flows being timed so as to occur at widely separatedpoints around the stator, wherein the timing is effected by a suitablyselected ratio of the number of impeller vanes to the number of statorslots 72. In this instance seven vanes and twelve slots are shown but itwill be apparent that other ratios are usable for peak flow distributioneffect at wide angles.

Referring to FIG. 4, a modification of the impeller is shown whereingrooves 2 and 4' are molded between raised wedges such as W. The groovesperform the function of the vanes of FIG. 2 and merely represent analternate form of an injection molded impeller. The stator would be thesame as heretofore described.

Referring now to FIG. 5, a detail of assembly is shown in an explodedview to illustrate the keying ribs, knurls, or flutes F milled orpressed into armature shaft 96 with impeller 60 being shown partiallyforced thereon so as to be keyed thereto, whereby a completesub-assembly comprises the armature, the stator and impeller.

Referring to FIGS. 10 and 11 a modification using essentially all moldedplastic components is illustrated wherein the body member meanscomprises an integral molding 200 having the cylindrical shell portion205, the outlet annular channel 210 and outlet conduit 215. The moldinghas cavity 220 forming a part of the housing for the armature 225 andterminating in a lip or edge 230 which abuts the cylindrical fieldmagnet 235. A second molded body member 240 is formed so as to effectthe stator for the pump by providing the longitudinal slots 245 withspaced fingers 247, surrounding the periphery of impeller 250. The slotscommunicate with arcuate grooves 255 molded into the wall of shellportion 205 (FIG. 11) and which grooves are recesses corresponding tothe longitudinal flow passages 44 of FIG. 3, However, any number of suchgrooves 255 may be provided. The lands 260 between grooves support themagnet 235 with an intermediate steel ring 265 fitting tightly over themagnet and force fitted against the inner surfaces of the lands.Accordingly, the magnet is radially located by the lands but securedlongitudinally by press fitting with longitudinal location beingdetermined by the peripheral edge 230. The impeller may have seven vanesand the stator twelve slots as in FIG. 2.

The body member 240, which integrally combines the stator islongitudinally locked by virtue of the ends of the stator fingers 247abutting the ends of various lands 260 and by the deformation radiallyof the end of housing portion 205, as by heat and pressure, into sealingengagement at 270 with the conically shaped flange of body member 240.

The body member is provided with the inlet ports 275 and accordingly itwill be apparent that flow takes place through the pump in essentiallythe same manner as heretofore described for FIG. 1, i.e., from ports 275to the impeller and thence to stator slots 245, grooves 255, annularchannel 210 and outlet conduit 215.

The armature is mounted in a manner similar to that heretoforedescribed, having shaft ends with bearing rotation in respective bodymembers and spring pressed ball bias in body member 200. However, theother body member may likewise be provided with a ball 260 as ananti-friction bearing. Metallic bushings such as 285 may be used forbearing support within the body members, if desired.

We claim:

1. A centrifugal pump comprising a rotary impeller having a plurality ofvanes and a stator comprising a plurality of longitudinally directedflow passages arranged peripherally about said impeller, wherein thenumber of vanes is unequal to the number of stator flow passages; anelectric motor of the brush and commutator type for driving saidimpeller; said vanes being equally angularly spaced and said flowpassages being equally angularly spaced, and wherein the number of vanesis related to the number of flow passages so as to effect a maximumpressure peak occurring in said passages in a predetermined sequence inorder to avoid occurrence of simultaneous maximum pressure peaks in anytwo passages and wherein maximum pressure peaks occur in said sequencethrough non-adjacent passages.

2. A centrifugal pump as set forth in claim 1, wherein the numericalratio of vanes and flow passages effects separation of sequentialmaximum pressure peaks through passages separated angularlyapproximately 3. A centrifugal pump as set forth in claim ll, whereinthere are seven vanes on said impeller and twelve passages in saidstator.

1. A centrifugal pump comprising a rotary impeller having a plurality ofvanes and a stator comprising a plurality of longitudInally directedflow passages arranged peripherally about said impeller, wherein thenumber of vanes is unequal to the number of stator flow passages; anelectric motor of the brush and commutator type for driving saidimpeller; said vanes being equally angularly spaced and said flowpassages being equally angularly spaced, and wherein the number of vanesis related to the number of flow passages so as to effect a maximumpressure peak occurring in said passages in a predetermined sequence inorder to avoid occurrence of simultaneous maximum pressure peaks in anytwo passages and wherein maximum pressure peaks occur in said sequencethrough non-adjacent passages.
 2. A centrifugal pump as set forth inclaim 1, wherein the numerical ratio of vanes and flow passages effectsseparation of sequential maximum pressure peaks through passagesseparated angularly approximately 150*.
 3. A centrifugal pump as setforth in claim 1, wherein there are seven vanes on said impeller andtwelve passages in said stator.